CN212336070U - Karst foundation variable-rigidity primary-secondary pile - Google Patents
Karst foundation variable-rigidity primary-secondary pile Download PDFInfo
- Publication number
- CN212336070U CN212336070U CN202022354082.3U CN202022354082U CN212336070U CN 212336070 U CN212336070 U CN 212336070U CN 202022354082 U CN202022354082 U CN 202022354082U CN 212336070 U CN212336070 U CN 212336070U
- Authority
- CN
- China
- Prior art keywords
- pile
- cage
- geogrid
- solidified soil
- karst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Piles And Underground Anchors (AREA)
Abstract
The utility model discloses a karst foundation variable-rigidity primary-secondary pile, which comprises a plurality of root piles, a geogrid cage and a solidified soil primary pile; the root pile and the geogrid cage are arranged in the solidified soil female pile, the solidified soil female pile is arranged in an overlying soft soil layer of the karst foundation, the upper portion of the root pile is located in the geogrid cage, and the axis of the root pile is parallel to the axis of the geogrid cage. The utility model discloses a karst ground becomes rigidity primary and secondary stake single pile and bears the weight of dynamic height, pile body atress reasonable, with few, the construction is simple, need not mud dado, former rock soil intensity is usable, can design into single-column single pile, with low costs, and the pile foundation engineering of karst ground is applied to the current embedded rock bored concrete pile of fungible.
Description
Technical Field
The utility model belongs to the technical field of the pile foundation, in particular to karst ground becomes rigidity primary and secondary stake.
Background
Karst is also called karst, and refers to a landform formed by soluble rocks under the action of erosion and mechanical destruction of surface runoff and underground water flow. The karst is distributed in each province of China, and the distribution area of the stratum containing the soluble rock is calculatedUp to 3.444X 106The characteristics of square kilometers, 1/3 occupying the area of the national soil, various karst forms, fluctuating rock surfaces, poor roof stability, dynamic change of karst water and the like are important factors influencing the stability of pile foundations in karst areas, the engineering quality and the safe use. When the karst cave is constructed in a karst area, the influence of the karst cave on the pile foundation is fully known, and a reasonable scheme is provided for the karst cave treatment of a specific project, which is always a difficult point and a key point of construction.
The influence of karst cave on pile foundation in karst area is mainly reflected in the following aspects:
1. collapsed hole
The reasons for the hole collapse are mainly as follows: failure of mud retaining wall and negative pressure of water level in the hole. When the connectivity of the karst cave is stronger or the covering layer is in the flow plasticity, slurry in the hole is easy to lose, the liquid level in the hole is reduced, pressure difference occurs outside the hole, and the slurry retaining wall fails to work, so that hole collapse is caused. And when the underground water level is higher than the water level in the hole, the water level in the hole generates negative pressure, and the hole wall is peeled off to cause hole collapse.
2. Borehole deviation
The causes of borehole deviation are mainly: the rock stratum weathering degree is uneven, the hardness of the two sides of the karst cave wall is uneven, the rock stratum conditions in the karst region are complex, the weathering degree is different, the hardness of the rock stratum is uneven, and when the impact hammer impacts the rock stratum, the footage speeds of the two sides are different, so that the drill hole is inclined. In addition, in the drilling process, when the pile hole runs through the karst cave wall, the hardness of two sides of the karst cave wall is uneven, so that the drill hole is deviated.
3. Slurry leakage
The reasons for slurry leakage are mainly as follows: the cracks are permeable and the solution cavity is not completely filled. The geological conditions of karst areas are complex, underground water is abundant, and when pile holes meet stratums where underground water flows, cracks are prone to seep water to cause slurry leakage. During construction, when the top plate of the karst cave is broken through by drilling and is connected with the karst cave, and no filling or half filling is carried out in the karst cave, a large amount of slurry leakage can be generated.
4. Clamping drill
The causes of sticking are mainly: unreasonable stroke selection, rock fall and irregular hole wall. If high-stroke impact is still adopted when the drill bit drills to be close to the top plate of the karst cave, the drill bit is easy to be clamped at different parts of the top plate rock of the karst cave after breaking the top plate rock of the karst cave, or loose stones fall between hole walls in the drilling process; and when the hole wall is broken in the drilling process, the drill hole is irregular in shape due to the shaking of the drill bit, and the drill jamming can also occur.
5. Failure of pile foundation
The reasons for causing the failure of the pile foundation mainly include: the rock surface of the karst cave fluctuates and the karst water changes dynamically. When the karst cave exists under the pile foundation or the karst cave is not completely treated, the compression performance of the overlying soil layer is uneven due to the fluctuation of the karst cave rock surface, so that the pile foundation is unevenly settled, and the pile foundation fails due to serious conditions. Meanwhile, dynamic change of karst water can corrode karst cave rock bodies and pile bodies, and the using effect of pile foundations is affected.
The main treatment methods for the above problems are pressure grouting, backfilling and steel casing follow-up.
Grouting method: when the karst cave rock mass is broken and cracks develop and the karst cave is filled with the fluid plastic filler, a grouting method can be adopted.
A backfilling method: when the karst cave wall is complete, the connectivity is poor, the underground water flow is small, no filling or half filling is carried out in the karst cave, and the required construction period is short, a backfilling method can be adopted.
A steel casing follow-up method: when the karst cave is easy to leak slurry and is communicated with peripheral karst caves, the property of a top plate covering layer is poor, or a steel casing follow-up method can be adopted to prevent the deviation of drilling holes and the like.
Despite the above measures, the construction of karst foundation piles is still frequent, and the phenomenon that the concrete pouring amount seriously exceeds the budget is still frequent. In addition, the follow-up depth of the steel casing is too large, so that the steel casing can not be pulled out.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a karst foundation becomes rigidity primary and secondary stake that the construction is simple, need not mud dado, former rock soil intensity is usable, with low costs.
The utility model adopts the technical proposal that:
a karst foundation variable-rigidity primary-secondary pile comprises a plurality of root piles, a geogrid cage and a solidified soil primary pile; the root pile and the geogrid cage are arranged in the solidified soil female pile, the solidified soil female pile is arranged in an overlying soft soil layer of the karst foundation, the upper portion of the root pile is located in the geogrid cage, and the axis of the root pile is parallel to the axis of the geogrid cage.
In the karst foundation variable-rigidity primary-secondary pile, the bottom of the tree root pile penetrates through a solidified soil primary pile and is embedded into a bedrock bearing layer of the karst foundation; the part of the solidified soil mother pile outside the geogrid cage is solidified soil; the upper part of the solidified soil mother pile located in the geogrid cage is plain concrete, the lower part of the solidified soil mother pile is solidified soil, and the thickness of the plain concrete is 1.0 m.
In the karst foundation variable-rigidity primary-secondary pile, the solidified soil primary pile is cylindrical and has the diameter larger than 1.0 m; the solidified soil primary pile is a down-the-hole impact high-pressure jet grouting pile, a high-pressure jet grouting pile or a cement mixing pile.
In the karst foundation variable-rigidity primary-secondary pile, the geogrid cage is of a cylindrical structure, the diameter of the geogrid cage is larger than 0.8m, and the length of the geogrid cage is 2.0 m-the thickness of a soft soil layer coated on the karst foundation; the geogrid cage is formed by rolling geogrids into one or more layers of cylindrical grid cages and then binding and fixing the geogrids by galvanized iron wires.
In the karst foundation variable-rigidity primary-secondary pile, the tree root pile is cylindrical, and the diameter of the tree root pile is 150-400 mm.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the utility model discloses earlier cover the soft ground to the basement rock and consolidate and handle to improve original soil body intensity, make follow-up the degree of difficulty of creeping into reduce, can dry-drill, need not the mud dado, reduced the trouble of mud outward transport and follow-up processing.
2. The upper 1m of the part of the solidified soil mother pile located in the geogrid cage adopts a concrete structure, the solidified soil mother pile is like a concrete table plate with the thickness of 1m, the root pile acts like a table foot, the load borne by the table surface is downwards transmitted to a base rock bearing layer through the solidified soil between the table foot and the table foot, the root pile and the solidified soil mother pile form a composite pile, and the compressive strength of the pile body of the composite pile is higher; the inside filler of geogrid cage is mainly for the solidification soil, compares with whole adoption commercial concrete, has reduced the utility model discloses a cost.
3. The utility model discloses a root stake diameter is little, uses small-size rig to be under construction, and the construction is simple and convenient. When meetting the cavern and facing same problem, handle degree of difficulty greatly reduced, reduced the utility model discloses a cost.
4. The utility model discloses do not destroy original stratum structure when the construction, make full use of original bedrock intensity, the dregs that the construction produced are few, have reduced dregs outward transport treatment cost, have reduced the utility model discloses a cost.
5. The utility model discloses pile body rigidity top-down of construction reduces in proper order, and this is unanimous with the axial stress distribution law when pile body atress, and the atress is reasonable, and the material strength of pile body structure can full play and utilization.
6. The utility model discloses the quantity, the diameter and the plane arrangement position of female pile stake footpath, root stake can change according to the load condition wantonly, no matter how big upper structure transmission load, all can carry out a post, has reduced the expense of pile foundation cushion cap, and then has reduced the utility model discloses a cost.
7. The geogrid cage of the middle female pile and the reinforcement cage of the root pile of the utility model have light weight, and special hoisting equipment is not needed during the lowering; and a mode of filling stones firstly and then grouting is adopted, so that the construction is simple.
8. When the height of a karst cave encountered by a drill hole is larger, sufficient dry and hard concrete is filled in the drill hole, and the drill hole is tamped by a column hammer to form the hole without generating a hole collapse phenomenon;
9. the utility model discloses the single pile bearing capacity is high, can consider according to the bearing capacity calculation result of composite pile during the design to adopt the load test achievement to check.
10. The utility model discloses root stake rigidity among the female pile is big, bears load postcuring soil and root stake and produces the compressive capacity that warp in coordination and produce less, and the lateral displacement that the event arouses is not big, and geogrid cage atress is limited, can not take place the condition of breaking.
11. As the composite pile, the strength of the root pile is fully exerted, so that the load borne by the root pile in the design can be considered as 80-90% of the ultimate bearing capacity, and the load borne by the solidified soil can be considered as half of the ultimate compressive strength.
In a word, compare with prior art, the utility model has the characteristics of the design construction is simple, and the material is few, and the expense is low etc, and the present rock-socketed bored concrete pile commonly used of fungible completely.
Drawings
Figure 1 is the utility model discloses a karst foundation becomes cross-sectional view of rigidity primary and secondary stake.
Figure 2 is the utility model discloses a karst foundation becomes rigidity primary and secondary stake top view.
In the figure: 1-a tree root pile; 2-geogrid cage; 3, covering a soft soil layer; 4-plain concrete; 5, solidifying the soil mother pile; 6-bedrock strata; 7-karst cave; 8-spindle-shaped protrusions; 9-hard concrete.
Detailed Description
The present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1-2, the utility model comprises five root piles 1, a geogrid cage 2 and a solidified soil mother pile 5; root stake 1 and geogrid cage 2 set up in solidified soil female pile 5, and solidified soil female pile 5 is arranged in the soft soil layer 3 that coats of karst ground, and five root stakes 1 are located geogrid cage 2, and the axis of root stake 1 is on a parallel with the axis of geogrid cage 2.
The bottom of the tree root pile 1 penetrates through a solidified soil mother pile 5. The root pile 1 is cylindrical, the root pile 1 is formed by drilling, then placing a reinforcement cage with a grouting pipe, filling broken stones and then grouting, the diameter of the root pile 1 is 150-400mm, cement slurry or cement mortar is selected for grouting, and a spindle-shaped protrusion 8 is formed in a karst cave after grouting.
The solidified soil parent pile 5 is cylindrical, and the diameter of the solidified soil parent pile is larger than 1.0 m; the solidified soil mother pile adopts a high-pressure jet grouting pile or a cement soil mixing pile. The part of the solidified soil parent pile 5, which is positioned outside the geogrid cage, is solidified soil; the upper part of the solidified soil mother pile 5 positioned in the geogrid cage 2 is plain concrete 4, the lower part is solidified soil, and the thickness of the plain concrete 4 is 1.0 m.
The geogrid cage 2 is of a cylindrical structure, the diameter of the geogrid cage 2 is larger than 0.8m, the geogrid cage 2 is formed by rolling geogrids into one or more layers of cylindrical grid cages and then binding and fixing galvanized iron wires.
The utility model discloses a construction method, including following step:
1) and digging soil to a designed elevation, leveling the field, and hardening the surface of the field by adopting premixed solidified soil when the soil layer of the field is softer.
2) And (3) reinforcing the soft soil layer 3 on the karst foundation by adopting a high-pressure jet grouting pile or a cement soil mixing pile according to equipment conditions to form a solidified soil female pile 5.
3) Before the primary setting and curing of the cured soil primary pile 5, the circular geogrid cage 2 is sunk to a certain depth above the top surface of the foundation layer 6 by pressing or vibrating.
4) Drilling holes at the designed positions of the root piles 1 in the geogrid cage by using a small-sized drilling machine, so that the drilled holes penetrate through rock bodies or rock body karst caves and enter a pile foundation bearing layer; stopping drilling if the karst cave 7 is met in the drilling process, filling dry and hard concrete with the slump smaller than 30mm into the drill hole, tamping the dry and hard concrete in the hole by using a column hammer slightly smaller than the aperture of the drill hole, and extruding the concrete 9 into the surrounding karst cave 7; the amount of concrete filled is enough to ensure that the drill hole is not communicated with the karst cave any more; and continuously drilling to the designed elevation.
5) And (3) placing a reinforcement cage provided with a grouting pipe in the drill hole, then filling broken stones into the drill hole, and then starting grouting until the pile top generates grout bleeding.
6) And repeating the steps 2) to 5) until all pile foundations are constructed.
7) Excavating all solidified soil 5 with the thickness of 1m at the inner upper end of the geogrid cage, filling plain concrete 4, vibrating, compacting and leveling, and exposing the reinforcing steel bars of the root piles 1 out of the upper end surface of the plain concrete 4 for being connected with main reinforcing steel bars in an upper structural column or a bearing platform.
Claims (5)
1. A karst foundation becomes rigidity primary and secondary stake, characterized by: the device comprises a plurality of tree root piles, a geogrid cage and a solidified soil mother pile; the root pile and the geogrid cage are arranged in the solidified soil female pile, the solidified soil female pile is arranged in an overlying soft soil layer of the karst foundation, the upper portion of the root pile is located in the geogrid cage, and the axis of the root pile is parallel to the axis of the geogrid cage.
2. The karst foundation variable-rigidity composite pile according to claim 1, which is characterized in that: the bottom of the tree root pile penetrates through a solidified soil mother pile and is embedded into a bedrock bearing stratum of the karst foundation; the part of the solidified soil mother pile outside the geogrid cage is solidified soil; the upper part of the solidified soil mother pile located in the geogrid cage is plain concrete, the lower part of the solidified soil mother pile is solidified soil, and the thickness of the plain concrete is 1.0 m.
3. The karst foundation variable-rigidity composite pile according to claim 1, which is characterized in that: the solidified soil female pile is cylindrical and has the diameter larger than 1.0 m; the solidified soil primary pile is a down-the-hole impact high-pressure jet grouting pile, a high-pressure jet grouting pile or a cement mixing pile.
4. The karst foundation variable-rigidity composite pile according to claim 1, which is characterized in that: the diameter of the geogrid cage is larger than 0.8m, and the length of the geogrid cage is between 2.0m and the thickness of a soft soil layer on the karst foundation; the geogrid cage is formed by rolling geogrids into a cylindrical grid cage and then binding and fixing overlapping repeated sections of the geogrids by galvanized iron wires.
5. The karst foundation variable-rigidity composite pile according to claim 1, which is characterized in that: the root pile is cylindrical, and the diameter of the root pile is 150-400 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022354082.3U CN212336070U (en) | 2020-10-21 | 2020-10-21 | Karst foundation variable-rigidity primary-secondary pile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022354082.3U CN212336070U (en) | 2020-10-21 | 2020-10-21 | Karst foundation variable-rigidity primary-secondary pile |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212336070U true CN212336070U (en) | 2021-01-12 |
Family
ID=74071297
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022354082.3U Active CN212336070U (en) | 2020-10-21 | 2020-10-21 | Karst foundation variable-rigidity primary-secondary pile |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212336070U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112049142A (en) * | 2020-10-21 | 2020-12-08 | 湖南科技学院 | Variable-rigidity composite pile of karst foundation and construction method thereof |
| CN115288124A (en) * | 2022-07-22 | 2022-11-04 | 广州环投南沙环保能源有限公司 | Tubular pile structure used in upper-soft lower-hard stratum and reinforcing method |
-
2020
- 2020-10-21 CN CN202022354082.3U patent/CN212336070U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112049142A (en) * | 2020-10-21 | 2020-12-08 | 湖南科技学院 | Variable-rigidity composite pile of karst foundation and construction method thereof |
| CN115288124A (en) * | 2022-07-22 | 2022-11-04 | 广州环投南沙环保能源有限公司 | Tubular pile structure used in upper-soft lower-hard stratum and reinforcing method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105840207B (en) | Construction method for comprehensive tunnel entering structure of large-span tunnel penetrating shallow-buried bias-pressure loose accumulation body | |
| WO2018210019A1 (en) | Pile formation method for down-the-hole impact rotary jet composite piles | |
| CN103233454B (en) | Processing method of soaking, vacuum preloading and slurry injecting for sand piles of collapsible loess foundation | |
| US20140026518A1 (en) | Construction method for root-type foundation anchorage and bored, root-type cast in-situ pile with anchor bolts | |
| CN102888834B (en) | A kind of construction method of major diameter broken stone pile | |
| CN106948340B (en) | A kind of construction method of the Manual excavated pile structure of high polymer grouting protection | |
| CN212336070U (en) | Karst foundation variable-rigidity primary-secondary pile | |
| CN113186903A (en) | Combined pile structure and construction method for treating insufficient bearing capacity of deep foundation pit construction pile by adopting combined pile structure | |
| CN107503362A (en) | A kind of compound antiskid piling wall retaining structure and construction method suitable for reservoir stability | |
| CN106522191A (en) | Transformer substation foundation treatment method and application thereof | |
| CN102808407B (en) | Construction method of soft-foundation reinforced concrete cast-in-place pile | |
| CN105780766A (en) | Drilling backfill end bearing pile foundation and construction method thereof | |
| CN112227401A (en) | Method for constructing bearing platform by filling stones in underwater stone abrupt slope area | |
| CN102626946A (en) | Manufacture method for concrete irregular fender post | |
| CN213448541U (en) | Arch bridge foundation of limestone foundation under deep round gravel layer | |
| CN111485571A (en) | Arch bridge foundation of limestone foundation under deep round gravel layer and construction method thereof | |
| CN214832589U (en) | Combined pile structure for treating insufficient bearing capacity of deep foundation pit construction pile | |
| CN206368375U (en) | A kind of electric power pylon basis | |
| CN205530218U (en) | Slip casting composite foundation suitable for high -rise building structural strengthening is rectified | |
| CN109113054A (en) | A kind of reclaimation area complex geological condition cast-in-situ bored pile multimachine combined construction method | |
| CN211200425U (en) | High side slope composite supporting construction that fills of gravel soil | |
| CN112049142A (en) | Variable-rigidity composite pile of karst foundation and construction method thereof | |
| CN205712084U (en) | A kind of boring backfill The End-bearing Piles Foundation | |
| CN113833012B (en) | Pile type adjustable fan foundation and construction method | |
| CN218204422U (en) | Foundation pit supporting structure of PRC tubular pile and prestressed anchorage cable combination |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |